This invention relates in general to a folding portable building and more particularly to a unit that can be transported as a standard cargo shipping container when in the closed position and can be opened, without heavy tools and equipment, to provide a shelter or enclosure several times the size of the closed container. The unit may be a shelter or a refrigerated storage container.
Portable prefabricated structures, such as mobile homes, have been used to provide temporary or semipermanent building space. However, as the size of the structure increases, the ease with which they can be transported is reduced. Large structures have to be divided into parts and transported separately on oversized trucks. When not in use, the structures require significant space for storage. Generally, a foundation or pier must first be constructed to provide a strong flat surface for the structure.
A number of folding structures have been devised to address these transportability and space problems. Two structures are shown in U.S. Pat. Nos. 4,545,171 and 4,891,919.
U.S. Pat. No. 4,545,171 discloses a structure having hinged roofs, floors and walls. Although its collapsible design makes it easier to transport, this structure is not made according to container shipping industry standards and requires specialized handling in transit. The structure also requires a concrete foundation, which can defeat any advantage for use as a temporary structure. The structure is designed to be permanently installed with various components being attached with nails and bolts. The interior surfaces, such as walls, paint, wallpaper, floors, and carpets are installed after assembly. Also, a gable is required above the front and rear wall sections in order to provide sufficient protection for the attic area from the weather. The gable increases the cost and complexity in fabrication and assembly of the collapsible structure.
U.S. Patent No. 4,891,919 discloses a house erected from and supported by a standard size cargo shipping container with hinged walls and floor panels. After the wall and floor panels are unfolded, the roof and end walls, which are transported inside the container, are removed and assembled to complete the house. Although transportation of the structure is simplified by the use of a standard size cargo shipping container, the complexity of assembly is increased through the use of the separable parts for the roof and walls which need to be lifted into position and attached. In fact, the patent states that assembly generally will take five days with four people. A specialized foundation is required to support the floor panels above the level of the container bottom. The arrangement of the hinges necessitates additional filler pieces to complete the floor and side walls.
In view of the foregoing, a need exists for a collapsible portable unit which meets the standards for the container shipping industry so that it is easily transportable. A need also exists for a portable unit which is easily and quickly assembled without a need for heavy equipment or tools and which can withstand significant adverse weather conditions. Finally, a need exists for a unit which can be assembled on a variety of terrains and surface conditions without the need for constructing a foundation or pier beforehand.